This disclosure relates in general to interoperating nodes in an information processing system, such as an Internet content delivery system or an Internet transaction acceleration system, and, but not by way of limitation, to control of connection protocols.
In an information processing system, including communications networks such as the Internet, two or more nodes can work together, for example exchanging information or sharing resources, using one or more protocols that enable the participating nodes to interoperate. Nodes need not be physically distinct from one another, though they may be; normally, however, nodes are at least logically distinct from one another in at least some respect. Interoperating nodes may be operated or managed by a single common authority or by independent, unrelated authorities. Two or more interoperating nodes are often independently operated or managed; the Internet includes many well known examples of the interoperation of two or more independently managed nodes.
A protocol can be standardized such that a node using the standard protocol should be able to interoperate, at least at the level of the protocol, with any other node using the standard protocol. Standard protocols that become widely adopted can permit a node to interoperate with many other nodes. One such widely adopted standard protocol on the Internet is the Transmission Control Protocol (TCP), which today enables almost every device on the Internet to interoperate with almost every other device. TCP operates at the connection layer and enables nodes to interoperate with other nodes by establishing communications connections.
Standard protocols often employ the use of attributes, such as configurable parameters and selectable algorithms, to permit the protocol to operate effectively in various situations. For example, TCP controls message size, the rate at which messages are exchanged, and factors related to network congestion through the use of attributes, including both by the use of parameters, such as the receive window field used in sliding window flow control and the retransmission timer, and by the use of algorithms, such as slow-start, congestion avoidance, fast retransmit, and fast recovery algorithms. It is often the case, in many standard protocols, that at each node the initial protocol attribute settings to be used for all the communication connections at the node can be independently specified by the operator of the node.
A protocol can also be customized, which in general requires that each node have installed customized components to enable the custom protocol. Without the customized components, the node would not be able to fully interoperate with other nodes using the customized protocol. Although it therefore may limit the total number of interoperable nodes, or in the alternative require widespread action to install the protocol customized components, or possibly both, protocol customization is used in order to add function, improve performance, increase flexibility, or modify other characteristics of a standard protocol, or to make available an entirely new customized protocol. Many customized protocols have been proposed for use on the Internet.